 <!DOCTYPE html>
 <html lang="en">
 <head>
     <meta charset="UTF-8">
     <meta name="viewport" content="width=device-width, initial-scale=1.0">
     <title>Document</title>
     <style>
        img{
            width: 500px;
            height: 500px;
        }
    </style>
 </head>
 <body>
     <div id="app">
        <img :src="arrs " alt="">
        <ul>
            <li v-for="(item,index) in arrs" @click=" arr = item">{{index + 1}}</li>
        </ul>
     </div>
     <script src="../Dev-tools/vue.js"></script>
     <script>
         new Vue({
             el:"#app",
             data:{
                 arrs:[
                    "img/1.jpg",
                    "img/2.jpg",
                    "img/3.jpg"
                 ],
                 arr:"img/2.jpg"
             }
         })
     </script>
 </body>
 </html>